Condensation polymers of pyridyl polybenzoic acids with glycols



me Sm 3,156,696 CONDENSATION POLYMERS F PYRIDYL POLY BENZOIC ACIDSWITHCLYCOLS- Ellis K. Fields, Chicago, Ill., as'signor to Standard OilCompany, Chicago, Ill., a corporation of Indiana No Drawing. FiledFeb.28,1961, Ser. No. 92,129 '3 Claims. (Cl. 260295) 6 This inventionrelates to a new class of polyesters and more specifically pertains topolyesters derived by reacting a polyhydr-ic alcohol and a pyridinepolybenzoic acid.

The new class of polyesters of this invention are polyesters derived byreacting a pyridine polybenzoic acid having the general formula:

wherein y is an integer from 2 to 3, with a polyhydric alco hol havingthe formula HO-(R) -OH wherein R is a divalent hydrocarbon groupcontaining from 2 to 20 carbon atoms such as ethylene glycol, propyleneglycol, dihydroxy cyclohexane, bis-methylol benzene and1,1-dimethyl-l,l-di(p-hydroxyphenyl) methane, also known as Bisphenol A.The polyesters can be employed as surface coating films, preferablyplast-icized with from about 1 to 5% by weight of a lower alkylphthalate such as dimethylphthalate, diisopropylphthalate,di-n-butylphthalate and the like. Such films can be conveniently bakedat about 100 C. to a tough, clear, non-brittle film. The polyesters ofthis invention, in general, have high softening points and high meltingpoints. The polyesters of this invention are also useful in thepreparation of polyurethanes by reacting the esters with isocyanates.

In the preparation of polyesters of this invention the ratio ofpolyhydric alcohol to pyridine polybenzoic acid can be varied from 1 to20 moles of polyalcohol per mole of acid. Copolyesters may be preparedby using, in addition to the pyridine polybenzoic acid, suchdicarboxylic acids as succinic, glutaric, adipic, pimelic, terephthalic,isophthalic, benzophenone dicarboxylic and diphenyl sulfone dicarhoxylicacids. Further modification can be obtained !by the use of monohydricalcohols and drying oils. The latter modification is useful in thepreparation of alkyd type resins.

The polyesters of this invention can be illustrated by the followingexamples.

Example 1 (n is in the range of 100 to 2000) (C H NO N, 2.33. Found: N,1.75.

This polyester softens at 220 C., and melts at 270 C.

3,156,696 Patented Nov, to, 1 964 It is soluble in dimethylformamide. Afilm deposited from its solution in dimethylformamide on glass is veryhard, but slightly brittle.

Addition of 2% by weight of polyester of di-n-butyl phthalate to thedimethyltormamide solution and subsequent baking at C. resulted in atough, clear film with no brittleness.

In addition to the polyester of Example 1, a high molecular weightpolyester can be obtained by reacting 2,6-(pcarboxyphenyl) pyridine withethylene glycol or ethylene oxide, one mole of glycol or oxide per moleequivalent to COOH group, to form the bis(hydroxyethyl) ester and thenheating this ester product under reduced pressure and from 250 to 350 C.while removing ethylene glycol split out.

Also 2,4,6-tri-(p-carboxyphenyl) pyridine can be reacted in a similarmanner as described in Example-l, preferably using the tri-acid chloridewith 3 moles of Bisphenol A to form a high molecular weight polyester.Ethylene glycol reacted with 2,4,6-tri-(p-carboxyphenyl) pyridineproduces an ester product which can be condensed, or reacted with adicarboxylic acid such as adipic acid to form a macromolecularcopolyester having predominantly OH groups or COOH groups as terminalgroups depending on the ratio of ester to adipic acid.

Example 2 Ethylene glycol is reacted with 2,6-di(p-carboxyphenyl)pyridine in the ratio of 5 parts by weight of the glycol per part of thepyridine dibenzoic acid. The excess of glycol over that required toreact with the carboxy groups is employed to have a fluid reactionmedium. The reaction is carried out in a nitrogen atmosphere in astirred closed autoclave starting with a nitrogen pressure of 50 to 100p.s.i.g. at ambient temperature. The autoclave contents are heated toabout 200 C. for 2 to 5 hours. Thereafter the excess glycol andby-product water is removed by distillation gradually reducing thepressure to 100 to 50 mm. Hg and distillation is continued. Whensubstantially all of the excess glycol is removed, the pressure isfurther reduced and the ester product is heated gradually to about 340to 350 C. with stirring at 5 to 10 mm. Hg while removing glycol splitout during the condensation reaction taking place at this highertemperature. When no further glycol is split out, the resulting highmolecular weight polyester is withdrawn and cooled in an inertoxygen-free atmosphere such as a nitrogen atmosphere. The high molecularweight polyester is a solid at room temperature.

What is claimed is:

1. A polyester obtained by the reaction of a pyridine polybenzoic acidhaving the formula wherein y is an integer from 2' to 3, with from 1 to20 moles of a diol selected from the class consisting of ethyleneglycol, propylene glycol, dihydroxy cyclohexane, bismethylol benzene and1,1-dimethyl-l,1-di(p-hydroxyphenyl) methane.

' AP1X iQ 1 Y P hQ it are se of .2 1 7. w ms ethylene wherein n is inthe range of from 100 to 2000, having an 10 glycol by distillation andwhilereducing the pressure to ambient softening point of 220C. and amelting point of 5 to 10 mm. Hg until substantially no further glycolre- 270 C; and is soluble in dim'ethylformamide. mains distilled andrecovering the polyester formed.

3. A polyester obtained by reacting ethylene glycol with2,6-di(p-carboxyphenyl) pyridine in the ratio of 5 References Cited 1nthe file of this patent PaTtS 9 glycol P P of Said dicarboxylic acid yWeight 15 Bergmann: -The Chemistry of Acetylene and Related in a mtrogenatmosphere at 200 C. until the bis-glycolate Compounds, page 0(Intel-science). 19 3. is formed, heating the bis-glycolate to atemperature in

1. A POLYESTER OBTAINED BY THE REACTION OF A PYRIDINE POLYBENZOIC ACIDHAVING THE FORMULA
 3. A POLYESTER OBTAINED BY REACTING ETHYLENE GLYCOLWITH 2,6-DI(P-CARBOXYPHENYL) PYRIDINE IN THE RATIO OF 5 PARTS OF GYLCOLPER PART OF SAID DICARBOXYLIC ACID BY WEIGHT IN A NITROGEN ATMOSPHERE AT200*C. UNTIL THE BIS-GLYCOLATE IS FORMED, HEATING THE BIS-GLYCOLATE TO ATEMPERATURE IN THE RANGE OF 250 TO 350*C. WHILE REMOVING ETHYLENE GLYCOLBY DISTILLATION AND WHILE REDUCING THE PRESSURE TO 5 TO 10 MM. HG UNTILSUBSTANTIALLY NO FURTHER GLYCOL REMAINS DISTILLED AND RECOVERING THEPOLYESTER FORMED.